docs: Timeouts in CTP

Signed-off-by: zirain <zirain2009@gmail.com>

site/content/en/latest/user/client-traffic-policy.md

@@ -410,5 +410,58 @@ Handling connection for 8888
 }
 ```
 
+### Enable HTTP request timeout
+
+This example configures the HTTP request timeout for the client, please check out the details [here](https://www.envoyproxy.io/docs/envoy/latest/faq/configuration/timeouts#stream-timeouts). 
+
+```shell
+cat <<EOF | kubectl apply -f -
+apiVersion: gateway.envoyproxy.io/v1alpha1
+kind: ClientTrafficPolicy
+metadata:
+  name: client-timeout
+spec:
+  targetRef:
+    group: gateway.networking.k8s.io
+    kind: Gateway
+    name: eg
+  timeout:
+    http:
+      requestReceivedTimeout: 2s
+EOF
+```
+
+Curl the example app through Envoy proxy:
+
+```shell
+curl -v http://$GATEWAY_HOST/get \
+  -H "Host: www.example.com" \
+  -H "Content-Length: 10000"
+```
+
+You should expect `428` response status after 2s:
+
+```shell
+curl -v http://$GATEWAY_HOST/get \
+  -H "Host: www.example.com" \
+  -H "Content-Length: 10000"
+*   Trying 172.18.255.200:80...
+* Connected to 172.18.255.200 (172.18.255.200) port 80
+> GET /get HTTP/1.1
+> Host: www.example.com
+> User-Agent: curl/8.4.0
+> Accept: */*
+> Content-Length: 10000
+>
+< HTTP/1.1 408 Request Timeout
+< content-length: 15
+< content-type: text/plain
+< date: Tue, 27 Feb 2024 07:38:27 GMT
+< connection: close
+<
+* Closing connection
+request timeout
+```
+
 [ClientTrafficPolicy]: ../../api/extension_types#clienttrafficpolicy
 [BackendTrafficPolicy]: ../../api/extension_types#backendtrafficpolicy